Can't log in to local Askbot; it simply refreshes /signin

edit

I installed a local copy of Askbot on my Mac (inside a corporate firewall), following the instructions at askbot.org/doc/index.html. It works in that I can bring it up as mac-mini.local:8000/ in a web browser, but:

• when I go to /account/signin/ and try to log in with the username/password I created on http://askbot.org (or even if I give a bad username/password), it simply refreshes the signin page.
• if I click "Create a password-protected account" I go to the account creation page, but if I try to create an account with my email address it tells me "this email is already used by someone else" (presumably because that account already exists on http://Askbot.org). The log/askbot.log file is empty (zero bytes); no errors are being written there.

How do I get it to work with local accounts, instead of using http://Askbot.org accounts? And why won't it work with my http://Askbot.org account?